This is a very handy tool that creates a perfectly conical recess for your countersunk screws.
The 1/4" flute is particulartly adapted to super scale embedding of micro countersunk screws. It can be used to hide offset hinges securing screw, recess scale panel access fasteners...
The 1/2" flute will be very handy for bigger countersunk screws like nylon screws, retract fasteners that need to be flush, or any other heavier duty job.
Both countersink are 6 flute types, tungsten carbide titanium oxyde coated and 100% made in the U.S.A. by one of the best machining tool manufacturer. Designed to machine aluminium, carbon and glass fiber.
They also work very well on kevlar fiber laminates at low speed.
Here is a video of the tool in action: